Add like
Add dislike
Add to saved papers

Effect of stem stiffness and bone stiffness on bone remodeling in cemented total hip replacement.

The hypothesis in this study is that the stem stiffness-to-bone stiffness ratio influences the incidence and type of bone remodeling and fixation with cemented total hip arthroplasty. Ninety-one patients with 99 hips had cemented stems using 3 different anatomic porous replacement designs. The APR I and APR II titanium stems with proximal porous coating on the proximal one fourth of the stem were cemented into 49 and 35 patients. The APR II-C stem, which is a cobalt-chrome stem only for cemented fixation, was cemented into 15 patients. These 3 different stem designs were used to study different metals as well as different stem shapes. The average follow-up was 4.3 years (range, 2-10 years) with all hips having 2 years' follow-up and 42 hips at least 5 years' follow-up. Bone remodeling was measured as stress shielding, calcar resorption, and distal hypertrophy on anteroposterior and lateral radiographs of the hip. Stress shielding was measured by the 4 grades described by Engh. A stem stiffness-to-femoral bone stiffness ratio was calculated from the plain radiographs with the stem stiffness known from the manufacturer and the bone stiffness calculated using measurements of the outer and inner diameters of the femur. There was no statistical difference for bone remodeling and fixation between the 3 stem shapes or 2 metal types used in these hips. No stem was loose, and only 10 had radiolucent lines. Stress shielding was statistically related to stem stiffness but was more strongly related to the axial stiffness ratio, mediolateral bending stiffness ratio, anteroposterior stiffness ratio, and torsional stiffness ratio. Stress shielding grade 3 and 4 was present in 20% of hips with a torsional stiffness ratio < 0.33, in 38% of hips with a torsional stiffness ratio of 0.34 to 0.5, and in 70% of hips with a torsional stiffness ratio > 0.5. Five-year results showed no statistical change in stress shielding, calcar resorption, and distal hypertrophy from the 2-year observations. The stem stiffness-to-bone stiffness ratio influenced bone remodeling but not fixation of these cemented stems.

Full text links

We have located links that may give you full text access.
Can't access the paper?
Try logging in through your university/institutional subscription. For a smoother one-click institutional access experience, please use our mobile app.

For the best experience, use the Read mobile app

Mobile app image

Get seemless 1-tap access through your institution/university

For the best experience, use the Read mobile app

All material on this website is protected by copyright, Copyright © 1994-2024 by WebMD LLC.
This website also contains material copyrighted by 3rd parties.

By using this service, you agree to our terms of use and privacy policy.

Your Privacy Choices Toggle icon

You can now claim free CME credits for this literature searchClaim now

Get seemless 1-tap access through your institution/university

For the best experience, use the Read mobile app